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(11) | EP 1 041 805 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A watermark-data-hiding apparatus |
| (57) The error detection code adding circuit adds error detection codes to watermark data.
An encrypting circuit encrypts the error detection code added watermark data according
to a first password. N encoders hide (embed) the encrypted error detection code added
watermark data in the content data by N different hiding algorithms, respectively.
A selector selects one of N encoders in response to a selection signal and outputs
the encoded and selected content data in which the encrypted error detection code
added watermark data is hidden. N decoders read watermark data and the error detection
codes from the encoded content data by N extracting algorithms corresponding to the
N hiding algorithms, respectively, to output N extracted content data including N
read watermark data and N error detection codes and N read watermark data, respectively.
Decrypting circuits decrypt the N read watermark data and the N error detection codes
from the N encoders according to a second password corresponding to the first password,
respectively. The error detecting circuits for detecting errors in the N error detection
codes, respectively. The selector selects and outputs one of the N extracted (inverse-hidden)
contents data according to the detected errors. |